The study of a collection of fish remains from the Eocene of Qatar (peninsula of the western coast in the Persian Gulf) reveals that the Midra (and Saila) Shales of that region belong to the Lutetian and not to the lower Eocene. This fish fauna proves to be very similar to the corresponding fauna of the Tethys of that age and shows more particularly an affinity with the one of the Lutetian of Egypt, as much from the systematic point of view as from the one of the climatic (tropical) and depositional (neritic) conditions.